In Junior High and High School, my transportation was walking, biking, or (rarely) the bus. The same was true for college, including those awful early mornings when I sometimes had to bike across town to campus from my parents' house, to sign on the college radio station. I always had to bike very close to a cannery next to the river, and let me just say that beets and even creamed corn are very unwelcome smells at 5:30am. Urgh.
There is a jogging & bike path along the Willamette River in Eugene, and I started riding on it a lot for exercise before and during my senior year of college. Looking back, I can say that it was a pretty short path, but an 8-9 mile loop seemed like a lot at the time!
I moved to Illinois to work in radio after college, and one of the guys there was a cyclist. It was a few years before I caved in, but during my final summer I biked around a lot on weekends. I liked it, enough that I kept at it when I moved to Sacramento.
Sacramento has a wonderful, extended bike path along the American River, and my new job's office was just off of one of the access points. I usually biked after work (during seasons with longer daylight), and soon met the man who became my husband... who loved to bike as a hobby. We did a lot of weekend riding together, and before long my uncle gifted me with a custom-made/equipped bike that was far superior to my old 10-speed (which apparently had been a few frame-sizes too small). The riding began in earnest then, and kept going after I left that job, went back to college for a Master's Degree, and then started a new job (which has nearby rural roads for riding on and a lot of other employees who like cycling).
I rode 10-15 mile stretches for many years, but added a little more distance while biking near the new office (15-16 miles just before I had my first child). After my daughter was born, the battle to lose the baby weight began and I increased the biking and the distance... and it got crazier after the second child. I've backed off from doing 28-30-mile rides on the long days (26 now), and after age 40 I had to crosstrain more frequently (I usually bike 3-4 days a week now, and typically not more than 2 days in a row. On the third day, my legs are slow, leaden, and aching, which is what they used to feel like on the 4th day when I was younger).
I'm lucky to live in this city right now, because the opportunities for biking are really good. There are also more bikeable days a year than in snow climates or ultra-rainy areas (some people DO bike in the rain, but I only do it accidentally. The brakes, handlebars, and tires get slippery, and puddles collect in your shoes). I'm sorry to see the area near my office becoming more developed (mostly more stop signs, lights, and traffic), but there's still a lot of open road and if the weather's good, I'll probably be on it.
Thanks to desertport for this wonderful topic. :)